The use of antibiotic therapy for infection management has increased dramatically in the area of periodontal disease as an adjunct to scaling and surgery treatment. With the emergence of antibiotic use in periodontal disease care, almost no work has been done in assessing the development of antibiotic resistance in dental plaque flora. By developing a DNA probe-based assay for the detection of antibiotic resistance markers for the periodontal pathogen, Bacteroides intermedius, it would be practical to deliver diagnostically valuable information to the dental practioner for those patient cases who have undergone antibiotic therapy. DNA probes for detection of erythromycin resistance will be developed by use of heterologous probes from related Bacteroides species which similar resistance patterns to B. intermedius. Molecular hybridization, DNA cloning and physical characterization of identified B. intermedius erythromycin sequences will be performed. Phase II objectives will involve patient clinical studies and development of three other antibiotic resistance probes. The long term objective is to provide a rapid, sensitive and accurate diagnostic battery of DNA probes for the detection of antibiotic resistant periodontal pathogens for commerical application.